smtpp - Man Page

SMTP proxy gateway service


smtpp [-d] [-l[[@]logfile]] [-pport] [-iinternal_ip] [-eexternal_ip] [-hdefault_ip[:port]]


smtpp is SMTP gateway service to allow internal users to access external SMTP servers.



Inetd mode. Standalone service only.


Daemonise. Detach service from console and run in the background.


Be silenT. Do not log start/stop/accept error records.


Never look for username authentication.


External address. IP address of interface proxy should initiate connections from.  By default system will deside which address to use in accordance with routing table.


Internal address. IP address proxy accepts connections to. By default connection to any interface is accepted. It´s usually unsafe.


Port. Port proxy listens for incoming connections. Default is 25.


Default destination. It's used if targed address is not specified by user.


Log. By default logging is to stdout. If logfile is specified logging is to file. Under Unix, if ´@´ preceeds logfile, syslog is used for logging.


Increase or decrease stack size. You may want to try something like -S8192 if you experience 3proxy crashes.


You can use any MUA (Mail User Agent) with SMTP authentication support. Set client to use internal_ip and port as a SMTP server. Address of real SMTP server must be configured as a part of SMTP username. Format for username is username@server, where server is address of SMTP server and username is user´s login on this SMTP server. Login itself may contain ´@´ sign. Only cleartext authentication is supported, because challenge-response authentication (CRAM-MD5, SPA, etc) requires challenge from server before we know which server to connect.


Report all bugs to

See Also

3proxy(8), ftppr(8), proxy(8), socks(8), tcppm(8), udppm(8), syslogd(8),


3proxy is designed by Vladimir 3APA3A Dubrovin (


January 2016 3proxy 0.8 Universal proxy server